Why Erika Christensen Felt Connected to Her 'Ten Days in the Valley' Character (Exclusive)

Erika Christensen wasn’t meant to play Kyra Sedgwick’s sister on Ten Days in the Valley -- at least, not the way creator Tassie Cameron originally envisioned. It was Sedgwick, who serves as an executive producer on the heart-pumping 10-episode mystery drama, who hand-picked the Parenthood star -- the two met “once upon a time” in New York, Christensen recalls -- to be her TV sibling.

“The script was written without me in mind and I wasn’t quite right for it the way it was on paper,” Christensen tells ET of her character, Ali Petrovich, the headstrong younger sister to Sedgwick’s Jane Sadler, a television writer whose daughter goes missing in the middle of the night. (Watch an exclusive scene between Christensen and Sedgwick from Sunday’s episode above.) That mystery serves as the driving force for the unraveling of secrets, lies and double lives.

“I had just gotten off another ABC show [the short-lived 2015 drama Wicked City] and I didn’t know that this was necessarily the right move for me. But then I read the script and I, despite myself, was so taken with it and so wrapped up with the story,” the 35-year-old actress says. Things moved quickly from there, though Christensen admits she “didn’t grasp” that she was the only actress they were meeting with for the part. “Tassie Cameron, our creator, Facetimed me and said, ‘You’re not right for what I’ve written, but you’ve given me an idea of what we can do with this character.’ So she wrote the character to be me.”

Well, not exactly like her, but as close to her real-life sensibilities that’s realistically possible in the fictional realm. Christensen revealed two major tweaks to Ali that were made that changed the trajectory of her relationship with Sedgwick’s character for the better.

“We thought that she would have a closer relationship professionally with Jane. She does Jane’s finances; she’s a business manager,” Christensen shares. “And also [her] age, which is an interesting thing to adjust between siblings. Originally, they were supposed to be closer in age and Tassie changed the character from 40 to whatever [age] I am [mid-30s]. We talked about how that would affect the sisters having grown up and ultimately, even though they have the same parents, their parents treated them differently.”

“They were a lot harder on and also didn’t have their own s**t together with the first kid. With the second kid, they had their s**t more together and were more compassionate toward Ali than Jane,” she adds. “It’s interesting how that ended up playing into the way that Ali ended up being maternal toward Jane.”

Christensen has a deep respect for Ali, who, on the surface, seems happily married (though cracks are already evident), has deep desires to become a mother (her struggles with infertility become a bigger focus) and has no patience for nonsense. She also serves as the audience’s mouthpiece for the eyebrow-raising decisions and situations Jane puts herself in.

“I feel like Ali doesn’t pull punches with Jane,” Christensen says, citing the first episode as setting the bar for their sisterly dynamic. “Just to have someone say, ‘No. Your kid is gone, you call the cops. Don’t be a dumb-dumb.’ As an audience member, it’s nice having someone representing your viewpoint. That’s what I liked about Ali. Have someone cut through the bull and hopefully, represent what [the audience] would like to say to Jane, even though Jane keeps bigger and bigger secrets from Ali as the story goes on.”

“There’s a point in episode eight where Ali says, as the secrets come out, ‘How do you not understand? You’re not grasping this. Can you be a normal person?’ And she can’t,” Christensen says of Jane’s inability to comprehend her dire reality. “That’s what Jane needs to do. She needs to understand the consequences of her actions and be a more considerate person. As much as you can completely admire her drive and her creativity, because I really do admire those qualities in people, in Jane’s case, she’s missing that ability to see things from other people’s points of view, which is ironic for a writer.”

Christensen promises that viewers are in for a wild, unsettling ride, and she feels comfortable saying that Jane’s daughter, Lake, is safe. As she tells it, the show isn’t about finding Lake and who was responsible for her abduction, but rather why she was taken in the first place. “It runs real deep. The stakes are high and that’s what you’re really starting to wrap your wits around in the final episodes,” she hints, adding that viewers have to suss out red herrings from valid clues. “That’s what the real shocker is: the why.”

As for who viewers should keep an eye on for the remainder of the season, Christensen points to Ali’s own husband, Tom, a recently laid-off newspaper journalist with hidden secrets of his own. “He’s got a whopper. He's not exactly who he appears to be and he's got various motives that crop up.”